Modern-day world football managers are split into two decisive camps when it comes to defending and marking. Most opt for man, some for zonal.
In truth, this debate only ever surfaces when a team concedes a goal from a corner kick, but the ideologies stretch much further than set pieces.
Marking is employed all over the pitch, with or without possession, and varies greatly with regard to circumstances.
Let's take a closer look at both approaches and determine which, if either, is more effective.
Each defender is assigned a player to mark. The objective is to stay close to your man and stop him from scoring or making a telling impact upon the game.
This can stretch from sticking to a player for free kicks and corners, all the way through to doggedly chasing one player for a full 90 minutes.
From the first corner of the game, you pick your man and mark him from then on to avoid confusion.
Rather than stick to a player, you guard a certain zone.
The six-yard box, when defending a corner, comprises of three or four zones in which defenders will stand. If the ball enters your zone, get rid of it. If it doesn't, don't worry about it.
In open play, many teams will drop into a predefined shape when out of possession to cover equal areas of the pitch.
Man marking is the de facto best way to defend a set piece, whether it's a corner, a close-range free kick or a punt into the penalty area from 45 yards.
The vast majority of managers employ this style, spending hours on the training ground perfecting it and pairing players to track each other's runs.
It comes with certifiable advantages, as you can effectively pick your matchups before the game starts. Your best three defenders can move to pick up their opponent's most dangerous scorers, leaving the rest to sort themselves out.
It's a relatively aggressive way of defending, pitting one man's physicality against another. It is for this reason that the slow or weak can be outgunned.
If you're facing six top-tier aerial players and don't have six to combat them, opting to man-mark them could see you concede easy goals.
Gerard Houllier would utilise the guarding of zones when managing Liverpool, and it backfired so often it made you wonder where the merits lay.
If you're guarding a zone, you're standing still. The attacker may have the advantage of a five- or 10-yard run on you, so he's in the air first, which means he gets to the ball first.
How are you supposed to beat your opponent in the air when he's already hurtling toward you?
Furthermore, problems arise when the ball drops between the zones. Players hesitate and remain unsure whose responsibility it is, and that's when the opposition usually pounces.
Moving away from set pieces, you'll see a large number of teams employing zonal marking in the open field.
Dunga's Brazil in the 2010 World Cup were the epitome of territorial defence, using a two-man pivot in Gilberto Silva and Felipe Melo to screen the back four.
They never rushed forward to retain the ball and nearly always stayed within 15 yards of each other. In fact, it was one of the best and most understanding midfield partnerships the game has seen.
Other examples are plentiful. Atletico Madrid, whilst facing Athletic Bilbao in last year's UEFA Europa League final, dropped into an impregnable wall of five to block midfield through-balls. They spread out evenly and divided the pitch between them.
Jose Mourinho's latest attempt to topple Barcelona in El Clasico saw Sami Khedira and Xabi Alonso form one of the finest holding duos since the aforementioned Brazilians.
Man marking in open play is a strange, fluid concept.
It is most commonly employed with regard to one specific player, rather than an entire team, as closely marking one dangerous opposition player can negate the threat they pose.
A modern interpretation of this is the revelation of the "suffoco"—a traditional midfield destroyer positioned higher up the pitch.
Marouane Fellaini has been used in this role against Manchester United, as have Ivan Rakitic against Real Madrid and Mario Mandzukic against Andrea Pirlo over the last several months.
So where's the distinction between man marking and high-line pressing?
What Spain do, when out of possession, is just out-and-out rushing. It's not man-focused, it's ball-focused.
The modern game is so fluid that it's almost impossible—or perhaps inadvisable—to utilise strict man marking to the scale of 10 players.
By almost all accounts, zonal marking in set pieces is a disaster waiting to happen. The main problem is that zones become blurred, players hesitate, and second balls are often converted to goals.
In open play, however, the zonal game rules supreme. The 2010 FIFA World Cup shifted world football towards territorial play and the emphasis of playing in relation to another.
It seems like we are edging away from it slightly with the development of the suffoco, but what Spain and Barcelona do simply cannot be regarded as man marking.
The marking at set pieces and in open play are two completely separate entities and evolve independent of each other. The traditional tussle at a corner will never die, but how teams organise themselves on the pitch is an ever-changing concept.